U.S. patent application number 12/225567 was filed with the patent office on 2009-10-08 for wholly aromatic thermotropic liquid crystal polyester resin composition, injection molded article thereof, and optical device using the molded article.
This patent application is currently assigned to Nippon Oil Corporation. Invention is credited to Satoshi Murouchi, Toshio Nakayama.
Application Number | 20090250662 12/225567 |
Document ID | / |
Family ID | 38541276 |
Filed Date | 2009-10-08 |
United States Patent
Application |
20090250662 |
Kind Code |
A1 |
Murouchi; Satoshi ; et
al. |
October 8, 2009 |
Wholly Aromatic Thermotropic Liquid Crystal Polyester Resin
Composition, Injection Molded Article Thereof, and Optical Device
Using the Molded Article
Abstract
Disclosed is a resin composition produced by melt-kneading a
white pigment and a wholly aromatic thermotropic liquid crystal
polyester. The resin composition can retain the excellent heat
resistance and moldability of the wholly aromatic thermotropic
liquid crystal polyester and have a satisfactory level of white
light reflectance. The resin composition comprises 35 to 100 parts
by weight of a white pigment particle and 100 parts by weight of a
wholly aromatic thermotropic liquid crystal polyester, wherein the
white pigment particle comprises 3 to 15 mass % of aluminum oxide
and 97 to 85 mass % of a white pigment produced by a process
including a roasting step and having a surface treated with the
aluminum oxide (provided that the sum total of the white pigment
and aluminum oxide is defined as 100 mass %). The resin composition
can be produced by a process including a melt-kneading step.
Inventors: |
Murouchi; Satoshi;
(Kawasaki-shi, JP) ; Nakayama; Toshio;
(Kawasaki-shi, JP) |
Correspondence
Address: |
WEINGARTEN, SCHURGIN, GAGNEBIN & LEBOVICI LLP
TEN POST OFFICE SQUARE
BOSTON
MA
02109
US
|
Assignee: |
Nippon Oil Corporation
Tokyo
JP
|
Family ID: |
38541276 |
Appl. No.: |
12/225567 |
Filed: |
March 22, 2007 |
PCT Filed: |
March 22, 2007 |
PCT NO: |
PCT/JP2007/056749 |
371 Date: |
September 24, 2008 |
Current U.S.
Class: |
252/299.6 |
Current CPC
Class: |
Y10T 428/10 20150115;
C09K 2323/00 20200801; C08K 9/02 20130101; H01L 33/60 20130101;
C08K 9/02 20130101; C08L 67/00 20130101 |
Class at
Publication: |
252/299.6 |
International
Class: |
C09K 19/06 20060101
C09K019/06 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 24, 2006 |
JP |
2006-083306 |
Claims
1. A resin composition, comprising 35 to 100 parts by mass of white
pigment particles obtained through surface treatment of 97 to 85%
by mass of a white pigment obtained by a production process
including roasting step with 3 to 15% by mass of aluminum oxide
(including its hydrate) (the total of the both being 100% by mass),
and 100 parts by mass of a wholly aromatic thermotropic liquid
crystal polyester, the composition being obtained through a melt
kneading process.
2. The resin composition according to claim 1, wherein the white
pigment is titanium oxide (TiO.sub.2) obtained by sulfuric acid
method.
3. A molded article having a molding surface with a reflectance of
480 nm wave of 80% or more, the molded article being obtained by
injection-molding the resin composition according to claim 1.
4. An optical device, which uses the molded article according to
claim 3 as a light emitting device member and/or a reflector.
5. The optical device according to claim 4, in which the light
emitting device uses white LED.
6. A molded article having a molding surface with a reflectance of
480 nm wave of 80% or more, the molded article being obtained by
injection-molding the resin composition according to claim 2.
7. An optical device, which uses the molded article according to
claim 6 as a light emitting device member and/or a reflector.
8. The optical device according to claim 7, in which the light
emitting device uses white LED.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a wholly aromatic
thermotropic liquid crystal polyester resin composition with
excellent reflectance of a specific wavelength light, an injection
molded article thereof, and an optical device using the molded
article, the optical device particularly using white light-emitting
diode (hereinafter referred to as "LED").
BACKGROUND OF THE INVENTION
[0002] Optical devices using LED such as a lighting system or
display device have been used in a wide range of fields. Such an
optical device comprises an LED element mounted on a circuit
pattern on a substrate by electrically conductive adhesive, solder
or the like with necessary wire connections by wire bonding, and a
reflector (reflecting frame) provided around the LED element for
enhancing the light utilization rate of LED, and the LED element
located within the reflector being sealed by a translucent resin is
used. As the white LED, various types are conventionally known, and
such LED is generally adapted, for example, to obtain white light
by combining a plurality of LEDs of green (G), blue (B), red (R)
and the like, or to utilize the effect of wavelength conversion by
mixing a fluorescent material to the sealing resin. For the
wavelength conversion, blue LED is mainly used, but ultraviolet ray
emitting LED is also usable as light source. As the reflector, a
molding of a resin composition filled with white pigment particles
composed of metal oxide may be used.
[0003] The reflector containing such resin composition is requested
to have heat resistance to heating process of solder or the like
for mounting the LED element on the substrate, heat generation
during thermosetting of the sealing resin, heating for connecting
an LED device to another member, heating in the use environment of
the LED device, or the like, and to maintain a high reflectance
during the subsequent period including usage. Further, the white
LED is particularly requested to maintain a satisfactory
reflectance in an area of 500 nm or less. From this point, a resin
composition comprising a thermotropic liquid crystal polyester
excellent in heat resistance, particularly, a wholly aromatic
thermotropic liquid crystal polyester having a melting point
exceeding 320.degree. C. and white pigment has come to be used for
the LED reflector (refer to, for example, Patent Documents 1 to
3).
[0004] Patent Document 1: Japanese Patent Kohyo Publication No. H6
(1994)-38520
[0005] Patent Document 2: Japanese Patent Application Laid-Open No.
2004-256673
[0006] Patent Document 3: Japanese Patent Application Laid-Open No.
2005-232210
DISCLOSURE OF THE INVENTION
[0007] However, such LED reflector including the wholly aromatic
thermotropic liquid crystal polyester has the problem of slightly
poor reflectance of 480-nm wave as a reflectance index of white
light (hereinafter referred to as "white light reflectance" in the
specification), compared with conventionally-used ones including a
polyamide-based resin composition.
[0008] It is commonly known to use, as the white pigment to be
added to the wholly aromatic liquid crystal polyester, white
pigment particles composed of a metal oxide having heat resistance
to the high treatment temperature and high opacifying strength.
Addition of such pigment is generally performed by melt
kneading.
[0009] Since the metal oxide constituting the white pigment
particles is an acidic compound, the wholly aromatic thermotropic
liquid crystal polyester is decomposed in the melt kneading process
due to continuous application of a large shearing force under
coexistence of the acidic compound with the melted wholly aromatic
thermotropic liquid crystal polyester, causing reduction in
molecular weight, generation of a low-molecular weight component,
or the like. This phenomenon is caused similarly also in the
plasticizing process for injection molding of the resulting resin
composition. The effect of such a phenomenon is considered to be
more significant as the melting point of the wholly aromatic
thermotropic liquid crystal polyester is higher, since the
phenomenon possibly becomes more notable at a higher
temperature.
[0010] With respect to the effect of the melt kneading process, in
production of the resin composition of white pigment and wholly
aromatic thermotropic liquid crystal polyester, on the surface
reflectance of injection molded article, in particular on the
reflectance in use as a reflector component for white LED device,
sufficient analysis and investigation of countermeasures have not
been performed yet.
[0011] The present invention thus has an object to attain a
satisfactory white light reflectance, in a resin composition
obtained from white pigment particles and wholly aromatic
thermotropic liquid crystal polyester through melt kneading
process, while retaining excellent heat resistance and moldability
of the wholly aromatic thermotropic liquid crystal polyester.
[0012] A first aspect of the invention relates to a resin
composition, comprising 35 to 100 parts by mass of white pigment
particles obtained through surface treatment of 97 to 85% by mass
of a white pigment produced by a production process including
calcination step with 3 to 15% by mass of aluminum oxide (the total
of the both being 100% by mass), and 100 parts by mass of a wholly
aromatic thermotropic liquid crystal polyester, the composition
being produced through melt kneading process.
[0013] In a second aspect of the invention, the white pigment in
the resin composition of the first aspect of the invention is
titanium oxide (TiO.sub.2) obtained by sulfuric acid method.
[0014] A third aspect of the invention relates to a molded article
having a molding surface with a reflectance of 480 nm wave of 80%
or more, which is obtained by injection-molding the resin
composition of the first or second aspect of the invention.
[0015] Further, a fourth aspect of the invention relates to an
optical device using the molded article of the third aspect of the
invention as a light emitting device member and/or a reflector.
[0016] In a fifth aspect of the invention, the light emitting
device in the optical device of the fourth aspect of the invention
uses white LED.
EFFECT OF THE INVENTION
[0017] According to the present invention, a resin composition
which can provide a molded article excellent in white light
reflectance can be obtained without impairing the excellent heat
resistance and moldability of wholly aromatic thermotropic liquid
crystal polyester through a general melt kneading process.
Therefore, a reflector using a surface of an injection molded
article of this resin composition as a reflecting surface,
particularly, a reflector suitable for white LED can be obtained,
and a light emitting device having excellent performances can be
consequently provided.
BEST MODE FOR CARRYING OUT THE INVENTION
Wholly Aromatic Thermotropic Liquid Crystal Polyester
[0018] Although there is not a particular limit on the wholly
aromatic thermotropic liquid crystal polyester according to the
present invention, its melting point is preferably 320.degree. C.
or higher since solder-resisting heat resistance is needed for the
use as LED reflector.
[0019] For obtaining a wholly aromatic thermotropic liquid crystal
polyester having a melting point of 320.degree. C. or higher, it is
good to use p-hydroxy benzoic acid in an amount of 40 mol % or more
as raw material monomer. In addition to this, other known aromatic
hydroxycarboxylic acids, aromatic dicarboxylic acids, and aromatic
dihydroxy compounds can be used in appropriate combination
therewith. Preferable examples thereof include a polyester obtained
only from aromatic hydroxycarboxylic acid such as p-hydroxybenzoic
acid or 2-hydroxy-6-naphthoic acid, and a liquid crystalline
polyester obtained from such polyester and an aromatic dicarboxylic
acid such as terephthalic acid, isophthalic acid or 2,6-naphthalene
dicarboxylic acid, and/or an aromatic dihydroxy compound such as
hydroquinone, resorcin, 4,4'-dihydroxydiphenyl or
2,6-dihydroxynaphthalene.
[0020] Particularly preferred is a wholly aromatic thermotropic
liquid crystal polyester obtained by polycondensing 80 to 100 mol %
of p-hydroxybenzoic acid (I), terephthalic acid (II), and
4,4'-dihydroxybiphenyl (III) (the total of (I) and (II) being 60
mol % or more) (including derivatives thereof) and 0 to 20 mol % of
another aromatic compound polycondensation-reactive with any one of
the compounds (I), (II), and (III).
[0021] In the production of the wholly aromatic thermotropic liquid
crystal polyester, for reducing the melt polycondensation time to
reduce the effect of thermal history during the process,
acetylation of hydroxyl groups of the monomer is preferably
performed prior to melt polycondensation. Further, for simplifying
the process, the acetylation is preferably performed by supplying
acetic anhydride to the monomer in a reaction tank. The acetylation
process is preferably performed using the same reaction tank as in
the melt polycondensation process. Namely, it is preferred to
perform the acetylation reaction of the raw material monomer with
acetic anhydride in the reaction tank, and raise the temperature
after completion of the reaction to transfer the reaction system to
polycondensation reaction.
[0022] The melt polycondensation reaction is performed along with
deacetylation reaction of the acetylated monomer. The reaction is
preferably performed using a reaction tank including a monomer
supplying means, an acetic acid discharging means, a melted
polyester extracting means, and a stirring means. Such reaction
tank (polycondensation device) can be appropriately selected from
conventionally known ones. The polymerization temperature is
preferably 150 to 350.degree. C. After completion of the
acetylation reaction, the temperature is preferably raised to a
polymerization starting temperature to start polycondensation, and
then raised to 280 to 350.degree. C. as final temperature at a rate
of 0.1.degree. C./min to 2.degree. C./min. As the catalyst of the
polycondensation reaction, compounds of Ge, Sn, Ti, Sb, Co, Mn, Mg
and the like can be used. The polycondensation temperature rises
corresponding to rise of the melting temperature of the produced
polymer according to the progress of polycondensation.
[0023] In the melt polycondensation, the wholly aromatic
thermotropic liquid crystal polyester with low polymerization
degree is extracted from the polymerization tank as in the melt
state, when its flow point reaches 200.degree. C. or higher,
preferably 220 to 330.degree. C., and supplied to a cooler such as
a steel belt or drum cooler to cool and solidify it.
[0024] The solidified wholly aromatic thermotropic liquid crystal
polyester with low polymerization degree is pulverized to a size
suitable for the following solid phase polycondensation. Although
the method for pulverization is not particularly limited, for
example, an impact grinder such as Feather Mill, Victory Mill,
Coloplex, Pulverizer, Contraplex, Scroll Mill, or ACM Pulverizer
produced by Hosokawa Micron Corporation, Roll Granulator that is a
pulverizing grinder mill produced by Matsubo Corporation, or the
like can be used. Particularly preferable is Feather Mill by
Hosokawa Micron Corporation. In the present invention, the particle
size of the pulverized matter is preferably within the range of
4-mesh passable to 2000-mesh impassable by industrial sieve (Tyler
mesh), further preferably within the range of 5 mesh to 2000 mesh
(0.01 to 4 mm), most preferably within the range of 9 mesh to 1450
mesh (0.02 to 2 mm) although it is not particularly limited
thereto.
[0025] The pulverized matter obtained in the pulverizing process is
supplied to solid-phase polycondensation process to perform
solid-phase polycondensation. The apparatus used for the
solid-phase polycondensation process and the operation condition
thereof are not particularly limited, and known apparatuses and
methods can be used. For the use as LED reflector, it is preferred
to perform the solid-phase polycondensation reaction until a one
having a melting point of 320.degree. C. or higher is obtained.
[0026] As the white pigment particles, those obtained through
surface treatment of 97 to 85% by mass of a white pigment with 3 to
15% by mass of aluminum oxide (the total of the both being 100% by
mass) are used. The white pigment referred to in the present
invention is the one not aluminum oxide. Any of the white pigment
can be used without particular limitation as long as it has heat
resistance to the melt kneading process with the wholly aromatic
thermotropic liquid crystal polyester and the injection molding
temperature, as well as the heating in solder mounting process or
the like.
[0027] As the white pigment obtained by a production process
including roasting step, titanium oxide (TiO.sub.2), zinc oxide
(ZnO), white lead (2PbCO.sub.3.Pb(OH).sub.2) and the like are
usable. Metal oxide-based white pigments excellent in heat
resistance are preferred. Particularly, rutile type titanium oxide
with high opacifying strength, which has an average particle size
of 0.1 to 0.5 .mu.m, is most preferred. Zinc oxide is also usable
depending on the taste of hue.
[0028] Of the metal oxide-based white pigments, titanium oxide
produced by sulfuric acid method including roasting step is
particularly preferred. The present inventors think that a
component of the white pigment which undesirably affects the white
light reflectance of a molded article of the composition obtained
by mixing it with the wholly aromatic thermotropic liquid crystal
polyester resin followed by melt kneading can be removed in the
roasting step.
[0029] As the method for surface-treating the white pigment with
aluminum oxide, conventionally known methods can be adapted. For
example, any of the method described in Japanese Patent Application
Laid-Open No. H5 (1993)-286721 and methods described as
conventional methods in this patent document may be used. Although
this patent document mainly relates to surface treatment of
titanium oxide, the same surface treatment can be performed to
other white pigments. The white pigment surface-treated with
aluminum oxide is also commercially available. Examples thereof
include "SR-1" produced by Sakai Chemical Industry Co., Ltd.
(rutile type titanium oxide, average particle size 0.25 .mu.m,
surface treatment agent Al.sub.2O.sub.3, treatment quantity
5%).
[0030] The present inventors think that the amphoteric property
(acidic and basic properties) and function as adsorbent of the
aluminum oxide are involved in the effect obtained by melt-kneading
white pigment particles of the white pigment surface-treated with
aluminum oxide (Al.sub.2O.sub.3) (including its hydrate) with the
wholly aromatic thermotropic liquid crystal polyester.
[0031] Namely, they are the function of adsorbing impurities in the
polymer and the function of mitigating effects such as promotion of
hydrolysis of the wholly aromatic thermotropic liquid crystal
polyester by the metal oxide as acidic compound by covering the
surface of the metal oxide-based white pigment.
[0032] A particularly notable point of the former function is to
adsorb an acetic acid-based compound left in the polymer when
polycondensation is performed with an acetyl derivative as monomer.
Therefore, this effect is most sufficiently exhibited when the
acetic acid-based compound is likely to be left within the system,
namely when a process for executing melt polycondensation by use of
an acetylated derivative of the monomer is included, and further
when acetylation of the monomer and melt polycondensation using the
resulting acetylated derivative are performed in the same reaction
tank.
[0033] When the amount of aluminum oxide is 3% by mass or less, the
effect of covering the surface of the white pigment and the effect
of adsorbing impurities in the polymer cannot be sufficiently
exhibited, and when it exceeds 15% by mass, a problem in handling
may be caused due to condensation or the like of the white pigment
particles. Therefore, as the white pigment particles, those
obtained through surface treatment of 97 to 85% by mass of white
pigment with 3 to 15% by mass of aluminum oxide (the total of the
both being 100% by mass) are used. The particularly preferable
range of aluminum oxide is 5 to 10% by mass.
[0034] For melt-kneading the wholly aromatic thermotropic liquid
crystal polyester with the white pigment particles composed of the
white pigment surface-treated with aluminum oxide, methods and
apparatuses used for known melt kneading can be suitably used. A
single-screw kneading machine, a twin-screw kneading machine,
Banbury mixer, pressure kneader and the like are usable, and the
twin-screw kneading machine is particularly preferred from the
point of ensuring suitable dispersion of the white pigment
particles.
[0035] The addition amount of the white pigment particles is within
the range of 35 to 100 parts by mass to 100 parts by mass of the
wholly aromatic thermotropic liquid crystal polyester. When the
amount is less than 35 parts by mass, sufficient whiteness cannot
be ensured, and when it exceeds 100 parts by mass, moldability is
significantly reduced, making it difficult to obtain a molding
surface having a white light reflectance of 80% or more.
[0036] Known inorganic fillers and organic fillers can be added to
the resin composition of the present invention in the range not
impairing the effect of the invention. Such fillers may be used
alone or in combination of two or more thereof.
Embodiments
(Production of Thermotropic Liquid Crystal Polyester: Melt
Polycondensation)
[0037] To a reaction tank made of SUS 316L (stainless steel) which
includes a double helical stirring blade and has an inner volume of
1.7 mm.sup.3, p-hydroxybenzoic acid (produced by Ueno Fine
Chemicals Industry, Ltd.) 298.3 kg (2.16 kmol), 4,4'-dihydroxy
diphenyl (produced by Honshu Chemical Industry Co., Ltd.) 134.1 kg
(0.72 kmol), terephthalic acid (produced by Mitsui Chemicals Inc.)
89.7 kg (0.54 kmol), isophthalic acid (produced by A.G.
International Chemical Co., Inc.) 29.9 kg (0.18 kmol), and
magnesium acetate (produced by Kishida Chemical Co., Ltd.) 0.11 kg
and potassium acetate (produced by Kishida Chemical Co., Ltd.) 0.04
kg both as catalyst were charged. After the polymerization tank was
nitrogen-substituted through double decompression-nitrogen
injection, acetic anhydride 385.9 kg (3.78 kmol) was added thereto,
and acetylation reaction was performed for 2 hours in a refluxing
state at a stirring blade rotating speed of 45 rpm while raising
the temperature to 150.degree. C. in 1.5 hours. After completion of
the acetylation, the temperature was raised to 310.degree. C. at a
rate of 0.5.degree. C./min in an acetic acid distillation state,
and polymerization reaction was performed for 5 hours and 20
minutes while removing acetic acid generated.
[0038] The reaction tank system was then sealed and pressurized to
14.7 N/cm.sup.2 (1.5 kgf/cm.sup.2) with nitrogen, and about 480 kg
of a low-polymerization degree wholly aromatic thermotropic liquid
crystal polyester that is the melt polycondensation reaction
product within the reaction tank was extracted through an
extraction port at the bottom of the reaction tank, and supplied to
a cooling solidification device described below. The temperature of
the melt polycondensation reaction product at this point was
310.degree. C.
(Cooling Solidification Process)
[0039] As the cooling solidification device, a device having a pair
of cooling rolls 630 mm in diameter with a roll-to-roll distance of
2 mm, and a pair of weirs with a distance of 1800 mm was used
according to Japanese Patent Application Laid-Open No. 2002-179979.
The pair of cooling rolls was rotated oppositely to each other at a
rotating speed of 18 rpm, the fluidized melting polycondensation
reaction product extracted from the polycondensation reaction tank
was gradually supplied to a recessed part formed by the pair of
cooling rolls and the pair of weirs, and retained within the
recessed part while adjusting the roll surface temperature by
adjusting the flow rate of cooling water within the pair of cooling
rolls. The surface temperature of the low-polymerization degree
wholly aromatic thermotropic liquid crystal polyester cooled and
solidified just after passed through the rolls was 220.degree. C.
The resulting sheet-like solidified matter 2 mm in thickness was
shredded into about 50-mm squares by a shredder (produced by Nikku
Industry Co., Ltd.).
(Pulverization Process and Solid-Phase Polycondensation
Process)
[0040] The shredded matter was pulverized using Feather Mill by
Hosokawa Micron Corporation to thereby obtain a solid-phase
polycondensation raw material. The crushed matter was passable
through a mesh having 1-mm opening. The crushed matter was stored
in a rotary kiln and subjected to solid phase polycondensation
under distribution of nitrogen while raising the temperature from
room temperature to 170.degree. C. in 3 hours, then to 280.degree.
C. in 5 hours, and further to 300.degree. C. in 3 hours, and about
480 kg of wholly aromatic thermotropic liquid crystal polyester was
thereby obtained.
(White Pigment Particle and Other Fillers)
[0041] White Pigment Particle 1:
[0042] Produced by Sakai Chemical Industry Co., Ltd.: Trade name
"SR-1": Rutile type titanium oxide obtained by sulfuric acid method
including roasting step, which is surface-treated with aluminum
oxide. Average particle diameter: 0.25 .mu.m. Mass % composition
ratio of titanium oxide to aluminum oxide equals to 95:5.
[0043] White Pigment Particle 2:
[0044] Produced by Ishihara Sangyo Kaisha, Ltd.: Trade name
"CR-60": Rutile type titanium oxide obtained by chlorine method
without roasting step, which is surface-treated with aluminum
oxide. Average Particle diameter: 0.21 .mu.m. Mass % composition
ratio of titanium oxide to aluminum oxide equals to 95:5
[0045] White Pigment Particle 3:
[0046] Produced by Sakai Chemical Industry Co., Ltd.: Trade name
"R-310": Rutile type titanium oxide obtained by sulfuric acid
method including roasting step, which is not surface-treated.
Average particle diameter: 0.20 .mu.m.
[0047] Glass Fiber:
[0048] "PX-1" produced by Asahi Fiber Glass Co., Ltd. (average
length: 3 mm, average diameter: 10 .mu.m)
(Production of Resin Composition)
[0049] To the wholly aromatic thermotropic liquid crystal
polyester, the white pigment particles 1 to 3 and glass fiber were
independently mixed in amounts shown in Table 1, and the mixture
was melt-kneaded at the highest temperature of the cylinder at
430.degree. C. by a twin-screw extruder (produced by Ikegai) to
thereby prepare each pellet.
(Production of Injection Molded Article)
[0050] The resulting pellet was made into an injection molded
article of 30 mm (width).times.60 mm (length).times.two-stage
thickness (3.0 mm/0.5 mm) (the length of each thickness part being
30 mm) as a specimen for white light reflectance by use of an
injection molding machine (SG-25 produced by Sumitomo Heavy
Industries, Ltd.) at cylinder temperature 420.degree. C., injection
rate 100 m/sec and mold temperature 80.degree. C.
(Measurement of White Light Reflectance)
[0051] For a surface of each specimen, measurement of diffuse
reflectance to 480-nm light was performed by use of a
self-recording spectrophotometer (U-3500: produced by Hitachi,
Ltd.). The reflectance is shown as a relative value to 100% diffuse
reflectance of a standard white board of barium sulfate. The result
is shown in Table 1.
TABLE-US-00001 TABLE 1 Composition (parts by mass) Reflectance (%)
Liquid White White White Specimen Specimen Crystal Pigment Pigment
Pigment Glass Thickness Thickness Polyester Particle 1 Particle 2
Particle 3 Fiber 3.0 mm 0.5 mm Example 1 100 75 15 84 83 Example 2
100 90 0 86 82 Example 3 100 75 5 85 82 Example 4 100 50 25 15 84
81 Example 5 100 50 15 82 80 Comparative 100 75 15 73 70 Example 1
Comparative 100 75 15 75 72 Example 2
[0052] Each of the resin compositions of Examples 1 to 5 and
Comparative Examples 1 to 2 had excellent injection moldability. In
comparison of Examples 1 to 3 with Comparative Examples 1 to 2,
which were differed in that White pigment particle 1 (satisfying
the requirement of the present invention) was used in the former as
the titanium oxide to be included, while White pigment particle 2
or White pigment particle 3 (not satisfying the requirement of the
present invention) was used in the latter, the value of reflectance
is apparently higher in the former than in the latter in both
specimen thickness conditions of 3.0 mm and 0.5 mm.
[0053] In Example 4 in which 50 parts by mass of 75 parts by mass
of White pigment particle 2 (not satisfying the requirement of the
present invention) contained in Comparative Example 1 was
substituted by White pigment particle 1 (satisfying the requirement
of the present invention), the value of reflectance is apparently
higher than in Comparative Example 1 in both specimen thickness
conditions of 3.0 mm and 0.5 mm.
[0054] All the compositions of Examples 1 to 4 which satisfy the
requirement of the present invention show high reflectance values
in both specimen thickness conditions of 3.0 mm and 0.5 mm.
INDUSTRIAL APPLICABILITY
[0055] The resin composition of the present invention has an
excellent reflectance in addition to excellent heat resistance and
injection moldability owned by a liquid crystal polyester resin
composition, and can be used as a member which is requested to have
a high reflectance such as a light emitting device member and/or a
reflector, particularly, a member for a light emitting device using
white LED.
* * * * *